The common name "surgeonfish" is derived from a characteristic that clearly distinguishes Acanthuridae from other fish families: the spines or "scalpels" on the caudal peduncle, one or more on each side. Based primarily on differences in this characteristic, the family can be divided into three subfamilies: The Acanthurinae, in which the peduncular spine rests in a groove and can be erected in defence during the fights, the Nasinae and Prionurinae in which the peduncular feature is arranged as one or more fixed blades on each side, that are sharp and elongate with age.
Place of origin:Western Indian Ocean
Indian Ocean, known from South Africa to Madagascar and Mauritius. Also known as Mauritius Tang. Usually seen on open reefs or swimming over mixed sand and rubble, adjacent to reefs to reefs to moderate depth. Reported to 60m, but usually occurs in much shallower waters. A territorial species that is nearly always found singly. Readily identified by the distinctive colouration of black with numerous white spots and a yellow tail. Length to 18cm.